This invention is concerned with a mould arrangement for use in a cyclically operating glassware forming machine, the arrangement comprising a mould comprising a bottom plate defining a bottom portion of a cavity of the mould in which molten glass is moulded in the operation of the machine, and two side portions defining side portions of the cavity, each side portion being movable in a cycle of operation of the machine to a first portion thereof in which it engages the bottom plate and the other side portion to co-operate in defining a mould cavity so that moulding can take place and to a second position thereof in which the side portions are separated to allow moulded glass to be removed from the mould cavity, the side portions also defining cooling passages passing upwardly through the side portions through which air can pass to cool the side portions, the cooling passages in each side portion each having an entrance in a bottom surface of that side portion, and the mould arrangement also comprising a plenum chamber extending beneath the first or the second position of each side portion and having one or more exits which open upwardly and communicate, when the side portion is above the plenum chamber, either directly or through vertical passages in the bottom plate, with the entrances of the cooling passages so that air is supplied to each cooling passage at substantially the same pressure, the plenum chamber also having an entrance connected to air supply means operable to blow air into the plenum chamber. Examples of such mould arrangements are described in detail in the specification of European Patent Application No. 0102820. Such a mould arrangement allows the passages in the side portions of the mould to be supplied with cooling air at a substantially uniform pressure and with a uniform flow pattern.
Mould arrangements as described in the last preceding paragraph have proved extremely successful in use but there are cases in which it is not possible to provide adequate cooling to all parts of the mould. For example, where containers of large diameter or of large width are being manufactured, the thickness of the mould near the joining line of the side portions of the mould has to be restricted in order to enable the mould to be fitted on to the fixed centres of the machine on which the mould arrangement is used. This is normally achieved by cutting away the side portions of the mould in a plane approximately at right angles to the joining line of the side portions. This results in the thickness of the mould in this region often being insufficient to enable cooling passages of sufficient size to give adequate cooling to be provided. Another example is the manufacture of large bottles in a mould containing more than one mould cavity so that there is a web of metal between the two cavities which is frequently thin so that sufficiently large cooling passages cannot be provided in this region.
It is an object of the present invention to provide a mould arrangement in which adequate cooling can be provided in regions where it cannot presently be so provided in the aforementioned mould arrangement.